Expansion-bolt.



maar) srarns narrante onirica.

GEORGE F. IVIINNIS, QFCHICAGO, ILLINOIS.

i EXPANSION-BOLT.

Application led December 29, 1915. Serial No.l69,143.

To all whom t may concern:

Be it known that I, GEORGE F. MINNIS, a

citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful lm'- provements in Expansion-Bolts, of which the following is a full, clear, and exact description. p

My invention relates to expansion bolts that depend upon the spread of the split casings to anchor the bolt in position.

The object of my invention is by a slight yet important change to lock the bolt against accidental withdrawal without incurring any additional cost in` the manufacture thereof, and to limit the spread of the halves of the casing so as to prevent them from splitting the material in which it is anchored. -This I accomplish by the means hereinafter fully described, and as particularly set forth in the claims.

In the drawings:

Figure -1 is a perspective view showing the exposed portion of my invention when in use. v

Fig. 2 is a side view of the bolt and one section of the split casing into which the bolt is screwed, anchored in a fragment of a wall.

Fig. 3 is a similar view of the bolt engaging both halves of the casing, looking at the same from a view point at right angles to that shown in Fig.2.

Fig. i is a plan view of the inner side of one of the halves of the casing.

The bolt shown in the drawings has a suitable polygonal head A; a square barrel a immediately'next said head; a cylindrical extension B of less diameter in axial alinement therewith, and a screw-threaded portion C which extends for the remainder of its length to its end b.

rl`he anchor for this bolt consists of a casing split longitudinally into equal halves D, D. Each. of these halves has semi-circular anges d projecting .from their outer ends; and each is provided with a` longitudinal central groove E, which extends from the outer flanged end ythereof a distance slightly greater than that between the squared lbarrel of the bolt and its screw-threaded end. rllhe inner ends e of these grooves are tapered almost to a' point, and the medial portion F only is threaded in such manner that when the flat sides of the two halves are properly placed together said grooves form a bore for Specification of Letters Patent. i I

Patented May 8, 19117.

the casing, the medial portion only of` which is engaged by the threaded portion of the bolt, and the inner end portion of which is tapered.

Before the halves of the casing are used, a washer G is placed alongside their outer ends just back of their flanges, and when the casing has been inserted in a properlylocated hole of the right diameter, the bolt is screwed into the same and-when the threaded end of said bolt passes beyond the threaded medial portions F of the sections of the casing the end of the bolt engages the tapered end of the grooves and begins to spread the inner ends of the.I half sections apart. This separation ofthe halves of the casing continues until the shoulder at the inner end of the squared portion a bears against the margins of the outer mouth of the casing, whereupon every effort to screw the bolt in farther binds the bolt tighter between the' medial screw-threaded fportion of the grooves and the outer endo the casing and spreads the casing halves farther apart and makes said halves bite into and secure a better hold in the surrounding material, while at the same time limiting the depth the bolt can be screwed and preventing such a separation of the inner ends of said halves that they would split the surrounding material (generally wood) in which they were inserted.

What l claim as'new is 1. rllhe combination with a bolt having a head, a shank having a barrel next the head of greater diameter than the remainder ofthe shank, which latter has a smooth barrel por# tion and a screwthreaded portion extending to its end, of ,acasing split longitudinally bore of which is provided with a medial screw-threaded portion and a smooth tapered portion between it and its inner ex- .i

tremity, and a washer surrounding the outer flanged ends thereof.

3. The combination with a ,bolt having'a head, a shank having a barrel next the head of greater diameter than the remainder of the. shank, which latter has a smooth barrel portion and a screw-threaded portion extending to its ends, of a easing split longitudinally into halves the outer ends of which are provided with lateral flanges and the bore of which is provided with a medial screwthreaded portion, a smooth portion between the same and its outer end and a smooth tapered portion between said medial threaded portion and its inner extremity, and a washer surrounding the outer anged ends thereof.

1,225,1iee

il. rlhe combination with a bolt having a head and a screw-threaded portion extending to its end, a easing split longitudinally o into halves the outer ends of which are provided With lateral flanges and the bore of which is provided with a medial screwthreaded portion, and a smooth tapered portionbetween it and its inner extremity.

In witness whereof l have hereunto set my hand this 27th day of December, 1915.

GEORGE F. MINNIS. 

